Startup and Steady-State Performance of a New Renewable Hydroprocessed Depolymerized Cellulosic Diesel Fuel in Multiple Diesel Engines

Author(s):  
Eric Bermudez ◽  
Andrew McDaniel ◽  
Terrence Dickerson ◽  
Dianne Luning Prak ◽  
Len Hamilton ◽  
...  

A new hydroprocessed depolymerized cellulosic diesel (HDCD) fuel has been developed using a process which takes biomass feedstock (principally cellulosic wood) to produce a synthetic fuel that has nominally ½ cycloparaffins and ½ aromatic hydrocarbons in content. This HDCD fuel with a low cetane value (derived cetane number from the ignition quality tester, DCN = 27) was blended with naval distillate fuel (NATO symbol F-76) in various quantities and tested in order to determine how much HDCD could be blended before diesel engine operation becomes problematic. Blends of 20% HDCD (DCN = 45), 30%, 40% (DCN = 41), and 60% HDCD (DCN = 37) by volume were tested with conventional naval distillate fuel (DCN = 49). Engine start performance was evaluated with a conventional mechanically direct injected (DI) Yanmar engine and a Waukesha mechanical indirect injected (IDI) Cooperative Fuels Research (CFR) diesel engine and showed that engine start times increased steadily with increasing HDCD content. Longer start times with increasing HDCD content were the result of some engine cycles with poor combustion leading to a slower rate of engine acceleration toward rated speed. A repeating sequence of alternating cycles which combust followed by a noncombustion cycle was common during engine run-up. Additionally, steady-state engine testing was also performed using both engines. HDCD has a significantly higher bulk modulus than F76 due to its very high aromatic content, and the engines showed earlier start of injection (SOI) timing with increasing HDCD content for equivalent operating conditions. Additionally, due to the lower DCN, the higher HDCD blends showed moderately longer ignition delay (IGD) with moderately shorter overall burn durations. Thus, the midcombustion metric (CA50: 50% burn duration crank angle position) was only modestly affected with increasing HDCD content. Increasing HDCD content beyond 40% leads to significantly longer start times.

Author(s):  
Eric Bermudez ◽  
Andrew McDaniel ◽  
Terrence Dickerson ◽  
Dianne Luning Prak ◽  
Len Hamilton ◽  
...  

A new Hydroprocessed Depolymerized Cellulosic Diesel (HDCD) fuel has been developed using a process which takes biomass feedstock (principally cellulosic wood) to produce a synthetic fuel that has nominally 1/2 cyclo-paraffins and 1/2 aromatic hydrocarbons in content. This HDCD fuel with a low cetane value (Derived Cetane Number from the Ignition Quality Tester, DCN = 27) was blended with naval distillate fuel (NATO symbol F-76) in various quantities and tested in order to determine how much HDCD could be blended before diesel engine operation became problematic. Blends of 20% HDCD (DCN = 45), 30%, 40% (DCN = 41) and 60% HDCD (DCN = 37) by volume were tested with conventional naval distillate fuel (DCN = 49). Engine start performance was evaluated with a conventional mechanically Direct Injected (DI) Yanmar engine and a Waukesha mechanical indirect injected (IDI) CFR diesel engine, and showed that engine start times increased steadily with increasing HDCD content. Longer start times with increasing HDCD content were the result of some engine cycles with poor combustion leading to a slower rate of engine acceleration towards rated speed. A repeating sequence of alternating cycles which combust followed by a non-combustion cycle were common during engine run-up. Additionally, steady state engine testing was also performed using both engines. HDCD has a significantly higher bulk modulus than F76 due to its very high aromatic content, and the engines showed earlier Start of Injection (SOI) timing with increasing HDCD content for equivalent operating conditions. Additionally, due to the lower DCN, the higher HDCD blends showed moderately longer Ignition Delay (IGD) with moderately shorter overall burn durations. Thus, the mid-combustion metric (CA50: 50% burn duration Crank Angle position) was only modestly affected with increasing HDCD content. Increasing HDCD content beyond 40% led to significantly longer start times.


Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).


Author(s):  
Seung Hyup Ryu ◽  
Ki Doo Kim ◽  
Wook Hyeon Yoon ◽  
Ji Soo Ha

Accurate heat release analysis based on the cylinder pressure trace is important for evaluating combustion process of diesel engines. However, traditional single-zone heat release models (SZM) have significant limitations due mainly to their simplified assumptions of uniform charge and homogeneity while neglecting local temperature distribution inside cylinder during combustion process. In this study, a heat release analysis based on single-zone model has been evaluated by comparison with computational analysis result using Fire-code, which is based on multi-dimensional model (MDM). The limitations of the single-zone assumption have been estimated. To overcome these limitations, an improved model that includes the effects of spatial non-uniformity has been applied. From this improved single-zone heat release model (Improved-SZM), two effective values of specific heats ratios, denoted by γV and γH in this study, have been introduced. These values are formulated as the function of charge temperature changing rate and overall equivalence ratio by matching the results of the single-zone analysis to those of computational analysis using Fire-code about medium speed marine diesel engine. Also, it is applied that each equation of γV and γH has respectively different slopes according to several meaningful regions such as the start of injection, the end of injection, the maximum cylinder temperature, and the exhaust valve open. This calculation method based on improved single-zone model gives a good agreement with Fire-code results over the whole range of operating conditions.


Author(s):  
Ziliang Zheng ◽  
Umashankar Joshi ◽  
Naeim Henein ◽  
Eric Sattler

Sasol isomerized paraffinic kerosene (IPK) is a coal-derived synthetic fuel under consideration as a blending stock with JP-8 for use in military ground vehicles. Since Sasol IPK is a low ignition quality fuel with derived cetane number (DCN) of 31, there is a need to improve its ignition quality. This paper investigates the effect of adding different amounts of Lubrizol 8090 cetane improver to Sasol IPK on increasing its DCN. The experimental investigation was conducted in a single cylinder research type diesel engine. The engine is equipped with a common rail injection system and an open engine control unit. Experiments covered different injection pressures and intake air temperatures. Analysis of test results was made to determine the effect of cetane improver percentage in the coal-derived Sasol IPK blend on auto-ignition, combustion and emissions of carbon monoxide (CO), total unburned hydrocarbon (HC), oxides of nitrogen (NOx), and particulate matter (PM). In addition, the effect of cetane improver on the apparent activation energy of the global auto-ignition reactions was determined.


Author(s):  
S. Vedharaj ◽  
R. Vallinayagam ◽  
S. Mani Sarathy ◽  
Robert W. Dibble

In this research, the flow and ignition properties of vegetable oil (VO) are improved by blending it with diethyl ether (DEE). DEE, synthesized from ethanol, has lower viscosity than diesel and VO. When DEE is blended with VO, the resultant DEEVO mixtures have favorable properties for compression ignition (CI) engine operation. As such, DEEVO20 (20% DEE + 80% VO) and DEEVO40 (40% DEE + 60% VO) were initially considered in the current study. The viscosity of VO is 32.4*10−6 m2/s; the viscosity is reduced with the increase of DEE in VO. In this study, our blends were limited to a maximum of 40% DEE in VO. The viscosity of DEEVO40 is 2.1*10−6 m2/s, which is comparable to that of diesel (2.3*10−6 m2/s). The lower boiling point and flash point of DEE improves the fuel spray and evaporation for DEEVO mixtures. In addition to the improvement in physical properties, the ignition quality of DEEVO mixtures is also improved, as DEE is a high cetane fuel (DCN = 139). The ignition characteristics of DEEVO mixtures were studied in an ignition quality tester (IQT). There is an evident reduction in ignition delay time (IDT) for DEEVO mixtures compared to VO. The IDT of VO (4.5 ms), DEEVO20 (3.2 ms) and DEEVO40 (2.7 ms) was measured in IQT. Accordingly, the derived cetane number (DCN) of DEEVO mixtures increased with the increase in proportion of DEE. The reported mixtures were also tested in a single cylinder CI engine. The start of combustion (SOC) was advanced for DEEVO20 and DEEVO40 compared to diesel, which is attributed to the high DCN of DEEVO mixtures. On the other hand, the peak heat release rate decreased for DEEVO mixtures compared to diesel. Gaseous emissions such as nitrogen oxide (NOX), total hydrocarbon (THC) and smoke were reduced for DEEVO mixtures compared to diesel. The physical and ignition properties of VO are improved by the addition of DEE, and thus, the need for the trans-esterification process is averted. Furthermore, this blending strategy is simpler and enables operation of straight run oils and fats in CI engine, replacing diesel completely.


Author(s):  
Alexander N. Arkhipov ◽  
Vladimir V. Karaban ◽  
Igor V. Putchkov ◽  
Guenter Filkorn ◽  
Andreas Kieninger

The evaluation of the blading clearance at the design stage is important for heavy duty gas turbine efficiency. The minimum clearance value at base load is limited by the pinch point clearance during startup and/or shutdown. Therefore, transient analysis is necessary for different operating conditions. 3D transient analysis of a whole engine is labor-intensive; however 2D axisymmetric analysis does not allow consideration of different 3D effects (e.g. twisting, bending, ovality, rotor alignment). In order to overcome these cost and time limitations, the combination of 2D, axisymmetric, whole-engine model results and the scaled deflections caused by different 3D effects is used for the axial and radial clearance engineering assessment during engine operation. The basic rotor and stator closures are taken from the transient analysis using a 2D finite element (FE) model composed of axisymmetric solid and plane stress elements. To take into account 3D effects of airfoil twisting and bending, the 3D FE displacements of the blade are included in the clearance evaluation process. The relative displacements of airfoil tip and reference point at the blade or vane hub are taken from 3D steady-state FE analyses. Then the steady-state displacements of the airfoils are scaled for transient conditions using the proposed technique. Different 3D rotor / stator effects (cold-build clearances and their tolerances, rotor position with respect to stator after assembly, casing bending, deformations of compressor and turbine vane carrier inducing of casing ovalization, exhaust gas housing movements, movements of the rotor in bearings and CVC and TVC support, etc.) are also included as a contributor to the clearances. The results of the calculations are analyzed and compared with good agreements to the clearances measured in engine testing under real operation conditions. The proposed methodology allows assessing the operating clearances between the stator and rotor during the design phase. Optimization of the running clearance is one key measure to upgrade and improve the engine performance during operating experience.


Author(s):  
Michael J. Bergin ◽  
Rolf D. Reitz

CFD simulations were conducted with the KIVA-3v code with improved spray and combustion sub-models. Combustion analysis was performed using micro-genetic optimizations for a 1.9L HSDI diesel engine at a high load operating conditions (∼15 bar imep). The study explored injector spray configurations, including the number of injector nozzle holes, the hole diameters, and their orientations. The engine swirl ratio and start-of-injection timing were also varied. The optimizations considered injector nozzles with 14, 12, 10 and 8 injector holes. Each configuration included consideration of a pair of injector holes. Variations in the orientation angle of the first hole were explored. For the second hole, both the orientation angle and the azimuthal spacing relative to the first hole were varied. The chosen parameters allowed the holes to be symmetrically spaced or coincident azimuthally. The performance of each simulation was based on a merit function which accounts for fuel economy, NOx and soot emissions. For the test conditions chosen, an 8-hole injector configuration was found to be the best. This is explained by the improved fuel spray penetration and mixing associated with a smaller number of large diameter nozzle holes. For all injector configurations, the optima selected groups of holes where the total angular spacing between holes was less than eight degrees. The optimum swirl ratio found was approximately that of the baseline engine design.


Author(s):  
Kent Froelund ◽  
Steve Fritz ◽  
John Hedrick ◽  
Jaime Garcia ◽  
Neil Blythe

Real-Time Da Vinci Lubricant Oil Consumption (DALOC™) measurements were made on a 2,942 kW (4,000 hp) EMD 16-710G3 locomotive diesel engine, as part of a program to evaluate prototype cylinder kits that hold the potential to reduce lubricating oil consumption and hence reduce exhaust particulate matter emissions towards meeting EPA Tier 0+ locomotive emissions certification. The DALOC technique uses sulfur dioxide (SO2) measured in the exhaust gas stream as a tracer for oil consumption. The engine was operated on an ultra-low sulfur diesel fuel (3 ppm by weight) and commercially available SAE grade 20W40 mineral-based lubricating oil (4,865 ppm by weight). Knowing the SO2 concentration in the exhaust, the air and fuel flow rates, and the lubricating oil consumption rate can be calculated in real-time, i.e. on a second-to-second basis. Use of this measurement technique on the locomotive engine application has proven to be a cost- and time-reducing tool for mapping steady-state lubricating oil consumption rate. Numerous prior publications describe the evolution of this technique over time as well as the prior art in the area of lubricant impact on emissions [1–12]. As part of this project, the lubricant oil consumption of 4 different cylinder kits were accurately quantified at 4 steady-state operating conditions typical of North American freight locomotive operation within less than 40 hours of actual engine running. Applying this measurement technique, a reduction of lubricant oil consumption of 75%+ in comparison to the baseline cylinder kits were documented.


Author(s):  
Vadym Mychaylovich Petuhov ◽  
Alexandr Vasilyevich Orobinsky ◽  
Natalya Anatolyevna Aksenova

The article presents the results of an experimental study and analytical evaluation calculations to check service life and increase durability of the needle bearing of piston head of connecting rod of a transport diesel engine. The primary reasons for the violation of the nominal operation of the main units of this mechanism have been established. Corresponding recommendations are proposed for carrying out accelerated tests for durability, reducing the thermal loads of the bearing operation and, as a consequence, improving the quality and service life of its entire piston group. Theoretical and experimental methods for determining the nominal life of the needle bearing of the piston head of the connecting rod (PHCR) of a transport diesel engine are proposed. The theoretical methodology allows obtaining reliable values of durability, taking into account the distribution of the working load over the rolling elements, as well as the mobility of the piston pin and sleeve. The performed calculations make it possible to correct and clarify the standard mathematical model for determining the nominal life of the PHCR needle bearing, depending on the distribution of loads on the rolling elements (rollers) under different operating conditions. This experimental technique with an acceleration factor of 10 is based on a twofold increase in the force effect on the elements of the PHCR needle bearing. This was achieved by assembling the bearing using a special technology, which is described in detail in the work. A significant decrease in the thermal effect and a decrease in radial loads on working rollers have been established. For ensure the regular oil supply into bearing during engine operation, a technique was developed to increase the load on the roller in contact zone, which significantly influenced durability and made it possible to conduct accelerated tests with a reliable yield. Its results of operational research and experience in design work correlate and are sufficiently explained by the developed methods, which allows them to be used for the improvement and modernization of connecting rods with needle bearings in PHCR. That is a permission to use these methodic for doing perfect and modern the needle bearing of the connecting-rod piston. Keywords: diesel, test procedure, needle bearing, rollers, piston head of the connecting rod, durability.


1988 ◽  
Vol 110 (3) ◽  
pp. 437-443 ◽  
Author(s):  
C. M. Urban ◽  
H. E. Mecredy ◽  
T. W. Ryan ◽  
M. N. Ingalls ◽  
B. T. Jett

The U.S. Department of Energy, Morgantown Energy Technology Center has assumed a leadership role in the development of coal-burning diesel engines. The motivation for this work is obvious when one considers the magnitude of the domestic reserves of coal and the widespread use of diesel engines. The work reported in this paper represents the preliminary engine experiments leading to the development of a coal-burning, medium-speed diesel engine. The basis of this development effort is a two-stroke, 900 rpm, 216-mm (8.5-in.) bore engine manufactured by Electro-Motive Division of General Motors Corporation. The engine, in a minimally modified form, has been operated for several hours on a slurry of 50 percent (by mass) coal in water. Engine operation was achieved in this configuration using a pilot injection of diesel fuel to ignite the main charge of slurry. A standard unit injector, slightly modified by increasing diametric clearances in the injector pump and nozzle tip, was used to inject the slurry. Under the engine operating conditions evaluated, the combustion efficiency of the coal and the NOx emissions were lower than, and the particulate emissions were higher than, corresponding diesel fuel results. These initial results, achieved without optimizing the system on the coal slurry, demonstrate the potential for utilizing coal slurry fuels.


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